The present invention relates to seals, and more particularly to O-ring biased radial seals.
One type of seal for sealing radially, i.e., against an inner or outer circumferential surface, is referred to as an O-ring energized cap ring seal. Such a seal typically includes a generally rigid, annular sealing member or ring having a circumferential sealing surface which engages inwardly against a shaft (“inwardly-sealing”) or outwardly against a bore (“outwardly-sealing”), the ring typically being formed of a relatively rigid polymer such as polytetrafluoroethylene (“PTFE”). An elastomeric ring (e.g., an O-ring) is disposed about or within the annular sealing member and pushes or biases the sealing member to maintain contact between the sealing surface and the shaft or bore.
When the sealing member is subjected to a torque sufficient to overcome static friction between the biasing member and the sealing member, the sealing member angularly displaces relative to the biasing member and slides against the biasing member surface in contact with the sealing member. Such sliding movement may abrade or otherwise damage the biasing member, which may ultimately result in failure of the seal.